Dislocation densities of GLIDCOP®, dispersion-strengthened copper with ultra-fine particles of aluminum oxide, were evaluated by employing the X-ray line profile analysis using the modified Williamson-Hall and modified Warren-Averbach methods. X-ray diffraction profiles for GlidCop samples with compressive strains applied at 200oC were measured with synchrotron radiation. The dislocation densities of GlidCop with compressive strain ranging from 0.6 to 4.3% were in the order of 3.2 × 1014–5.8 × 1014 m-2. The dislocation density increased with increasing the compressive strain within the measured strain range.